Flow control mechanisms are provided in many digital radio protocols, including Bluetooth, to allow a receiver to request that a transmitter pause transmission for a short period of time before resuming data transmission. These mechanisms are useful in preventing loss of frames (or packets) where there are short bursts of high throughput which might otherwise overload the receiver. Other protocols, such as IEEE 802.11 (also known as ‘Wi-Fi’), provide no such flow control mechanism as it is expected that the receiving device will be able to cope with the maximum possible data throughput.
Typically Wi-Fi enabled devices have had relatively powerful processors and large amounts of memory (e.g. laptop computers). However, as Wi-Fi connectivity is integrated into smaller devices, such as mobile telephones and PDAs (personal digital assistants), the power consumption of the Wi-Fi modules becomes important. Use of a soft MAC (media access controller), where most of the code resides on the host processor and only time critical operations are performed on the MAC itself, uses a lot of power and as a result is not suitable for highly mobile applications. An alternative is to use a single Wi-Fi chip solution, which integrates a 2.4 GHz radio, MAC and other radio components and has extremely low power consumption.